Scry 2, then draw a card.
Flashback {4}{U}

Double target creature's power and toughness until end of turn.
Flashback {1}{G}

Flying
Creatures you control with base power 1 or less get +1/+0.

Flash
When Seal Away enters, exile target tapped creature an opponent controls until Seal Away leaves the battlefield.

Whenever a land you control enters, scry 1. If that land is a Ruin, scry 2 instead.

When Seer of the Aspirants enters, surveil 1.
Wander {2}{G}

Set Ablaze deals 2 damage to any target. You may discard up to two cards, then draw that many cards.

When Shaman of Rime's Fury enters, create a 0/0 colorless Spirit creature token. Put a number of +1/+1 counters on that token equal to the total number of instant and/or sorcery cards you own in exile and in your graveyard.

Flying
Short-Fused Firebird attacks each combat if able.
Whenever Short-Fused Firebird attacks, the next flashback cost you pay this turn costs {2} less.

Flash
Whenever you cast Siflir, Elder Pawn or another spell, if you paid an alternate or additional cost to cast it, draw a card.
Wander {3}{U}{U}

Enchant artifact or creature
Enchanted permanent loses all abilities and doesn't untap during its controller's untap step.
Wander {3}{U}{U}

Choose one —
• Exile target noncreature spell.
• Return target creature spell to its owner's hand. Draw a card.

When Skarni Patrol enters, if you control an Equipment, you draw a card and you lose 1 life.
Pay 2 life: The next equip ability you activate this turn costs {2} less to activate. Activate only once each turn.

Whenever Skarni Raider attacks, if it's equipped, you draw a card and you lose 1 life.

When Slumbering Grove enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
Spellcharge 8

When Snowscryer enters, surveil 3.

{T}: Add one mana of any color.
At the beginning of combat on your turn, if you've spent at least five mana to cast spells this turn, untap Speaker of Endless Winter and put a +1/+1 counter on it.

Whenever a Ruin you control becomes spellcharged, put a +1/+1 counter on Speaker of the Forebears.
Sacrifice Speaker of the Forebears: Add an amount of {R} equal to the number of +1/+1 counters on it.

Create a 1/1 green Saproling creature token for each permanent card you own in your graveyard and in exile.
Flashback {2}{G}{G}

As an additional cost to cast this spell, exile any number of permanent cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.
Deathtouch
When Sporeback Jargah dies, return a card exiled with it of an opponent's choice to its owner's hand.

Flying
Springsoarer enters with a +1/+1 counter on it if a creature you controlled dealt combat damage to a player this turn.
Wander {2}{U}

Flying
When Squallrunner Duo enters, create a 1/1 white Human creature token.
Nontoken creatures you control that have attacked this turn have wander {2}.

Flash
Whenever you cast a spell during an opponent's turn, tap up to one target artifact or creature.

Vigilance
{T}: Add {C}.
{T}: Add {C}{C}. Activate only if Steadfast Gatekeepers is a creature.
Spellcharge 3

Equipped creature gets +1/+3 and has vigilance.
Equip {5}. This ability costs {2} less to activate if you have at least 3 life more than your starting life total.